I live in an 18 unit building that is 20 years old. We started having water hammer issues about 10 years ago. One of the tenants was a plumber and he told us that the issue was often solved by turning OFF the water taps to front loader washing machines when you are not using them. To our surprise it works. We still have a little water hammer but it is nowhere like it was. When we get new people in the block we tell them to turn their taps off. Some don’t believe us but after a bit of noise they do!
Apparently the solenoids that are used to turn the water on and off in front loaders compress and expand unless they are isolated from the water system by being turned off. It is worse in units designed in the days when most people had top loaders like ours was.
I would ask your neighbours to give it a try. It is cheaper than a plumbing investigation!